1. Field of the Invention
The present invention relates to a method and apparatus for rinsing and priming an exchanger having two compartments separated by a semipermeable membrane. The first compartment is intended for the extracorporeal circulation of blood to be treated, and the second compartment is adapted to be connected to a dialysis liquid circuit.
2. Description of The Prior Art
Even though devices for the extracorporeal treatment of blood are carefully manufactured and are sterilized during the final stage of the manufacturing process, it is necessary to thoroughly rinse the exchangers before they are used. The purpose of rinsing is to eliminate possible manufacturing and sterilization residues which could lead to undesirable reactions (such as hypersensitivity reactions) if they were to pass into a patient's blood.
During the rinsing stage, sterile physiological liquid is usually circulated from a storage bag into the first compartment (blood compartment) of the hemodialyzer. In addition, liquid produced by a dialysis liquid generator, generally integrated with the dialysis monitor, circulates through the second compartment (dialysis compartment).
The sterile liquid intended for rinsing the blood compartment is generally circulated by means of a pump usually used for the circulation of the blood to be treated.
In order to ensure effective rinsing of the blood compartment, French Patent Application No. 2,566,273 proposes a washing method wherein a predetermined quantity of physiological saline solution, such as an aqueous solution of 0.9% sodium chloride, is circulated in the blood compartment and then immediately evacuated. Next, fresh physiological saline solution is circulated in the blood compartment. Finally, fresh physiological saline solution from a second source is circulated through the blood compartment.
Although the rinsing method described above has the advantage of efficiently eliminating possible residue in the blood compartment of the hemodialyzer, it nevertheless causes considerable inconvenience to the hospital staff charged with the preparation of a hemodialysis session.
Another problem inherent in the prior art method is that dialysis liquid used for rinsing the dialysate compartment may become contaminated. It is possible for substances such as bacterial derivatives to diffuse through the semipermeable membrane towards the blood compartment.
In addition, when the blood compartment is connected to the source of the blood to be treated, it is very difficult to control the pressures exerted inside each of the compartments of the hemodialyzer and to prevent substances which may be present in the dialysis liquid from passing through the membrane. The more permeable the membrane, the greater the problem.
Hypersensitive reactions caused by contaminated blood may occur during the first few minutes of the hemodialysis session and require the physician to interrupt the session immediately.
In order to improve the bacteriological quality of dialysis liquid, it has been proposed to filter the liquid before use. This requires the use of filters that increases the cost and maintenance operations to the dialysis liquid generator. In addition, the efficiency of these systems has been mediocre. Another problem with the filtration method is that there are bacterial derivatives capable of producing a biological effect whose size is so small that it is difficult to retain them by filtration. The prior art systems require in-line means for verifying filtration efficiency, as well as a safety device that prevents the use of dialysis liquid that has been inadequately filtered.
Accordingly, it is an object of the present invention to provide a method and apparatus for rinsing and priming an exchanger which does not have the drawbacks of the prior art and effectively eliminates manufacturing and sterilization residues.
An additional object of the present invention is to provide a method and apparatus for rinsing and priming of an exchanger to overcome the contamination caused by the dialysis liquid generator.
Another object of the present invention is to provide a simple and fast method and an apparatus for rinsing and priming a hemodialyzer.
Another object of the present invention is to provide a method and an apparatus for rinsing and priming a hemodialyzer that effectively rinses the hemodialyzer to prevent hypersensitivity reactions from occurring at the beginning of the treatment session.
A further object of the present invention is to provide an inexpensive method and apparatus for rinsing and priming an exchanger.
In addition, an object of the present invention is to provide a method and apparatus which is particularly suitable for an exchanger fitted with a membrane having high water permeability.
Additionally, an object of the present invention is to provide a method and a device for rinsing and priming an exchanger that does not require the use of a dialysis liquid generator.
Additional objects and advantages are set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.